The invention relates to a magnetic friction clutch, having at least two clutch parts supported so that they are rotatable relative to each other around an axis of rotation, where a first clutch part has at least two clamping jaws that are movable somewhat toward each other and away from each other, where a second clutch part situated between the clamping jaws is disk-shaped, where the clamping jaws may be pressed against the second clutch part by the magnetic force of a variable magnetic flux which is carried in the clutch parts in a soft magnetic material in order to form a frictionally engaged connection between the clutch parts, where the second clutch part has a plurality of soft magnetic ring zones permeated by the magnetic flux, which extend in the circumferential direction and are separated from each other in the radial direction by slots running in the circumferential direction, where ring zones that are adjacent to each other in the radial direction are connected to each other by bridging links.
A friction clutch of this sort, in which the second coupling part is designed as a thin, flat disk, is known from DE 10 2004 015 655 A1. The disk has pressing surfaces on both sides, which are perpendicular to an axis of rotation around which the clutch parts are rotatably supported relative to each other. A magnetic circuit fed by an electromagnet is carried in a soft magnetic material of the clutch parts in such a way that the magnetic flux alternates between the clutch parts at twelve flux crossing points situated one after another in the direction of flow. In the first clutch part, the magnetic flux flows through ring-shaped soft magnetic flux conductors which are situated concentric to an axis of rotation around which the clutch parts are rotatably supported relative to each other. At the same time, the magnetic flux flows several times in sequence from the one clamping jaw axially through the second clutch part to the other clamping jaw and then back from the latter through the second clutch part to the first-named clamping jaw. The flux conductors are designed as sheet packs, which have a plurality of soft magnetic layers running in the circumferential direction which are electrically insulated from each other transversely to the direction of flow of the magnetic flux. The disk-shaped second clutch part is made from a sheet of metal panel with the help of a punching process. In the punching process, ring-segment-shaped slots are punched out of the metal sheet between ring zones. Between adjacent slots in the circumferential direction narrow bridging links remain, which join the ring zones together into a single piece. To keep the magnetic scatter flux between the ring zones to a minimum, it is advantageous for the radial bridging links to be as narrow as possible. Furthermore, an effort is made to make the walls of the second clutch part thin, in order to keep the mass inertia low. But on the other hand the bridging links should not fall below a certain minimum cross section, so that the second clutch part will have adequate mechanical stability and can transmit the torque which is exerted on the clutch parts. So that the friction clutch will enable rapid magnetic field changes, and thus highly dynamic adjustments, it is also advantageous for the second clutch part to be subdivided into the greatest possible number of ring-shaped flux conductors. However, the requirements for mechanical stability of the second clutch part permit only a relatively small number of flux conducting rings.